نتایج جستجو برای: nanoporous membrane

تعداد نتایج: 393570  

2011
Dingsheng Wang Peng Zhao Yadong Li

Although Raney nickel made by dealloying has been used as a heterogeneous catalyst in a variety of organic syntheses for more than 80 years, only recently scientists have begun to realize that dealloying can generate nanoporous alloys with extraordinary structural characteristics. Herein, we achieved successful synthesis of a variety of monodisperse alloy nanoporous nanoparticles via a facile c...

2006
Danilo Zschech Dong Ha Kim Alexey P Milenin Sigrid Hopfe Roland Scholz Petra Göring Reinald Hillebrand Stephan Senz Craig J Hawker Thomas P Russell Martin Steinhart Ulrich Gösele

Ordered gold nanoparticle arrays with high lateral density of 6.87 × 1010 nanoparticles cm−2, which are stable up to temperatures of 600 ◦C, were fabricated. To this end, nanoparticles formed by thermal vacuum evaporation of Au were immobilized within the pores of nanoporous silicon wafers prepared by block copolymer lithography coupled with dry plasma etching. Even after high-temperature treat...

2008
Patrick E. Hopkins Pamela M. Norris Leslie M. Phinney Steven A. Policastro Robert G. Kelly

The reduction of nanodevices has given recent attention to nanoporous materials due to their structure and geometry. However, the thermophysical properties of these materials are relatively unknown. In this article, an expression for thermal conductivity of nanoporous structures is derived based on the assumption that the finite size of the ligaments leads to electron-ligament wall scattering. ...

Journal: :Optics express 2010
Nimi Gopalakrishnan Kaushal S Sagar Mads Brøkner Christiansen Martin E Vigild Sokol Ndoni Anders Kristensen

Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (deltan = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part of a nanoporous polymer block hydrophilic. A propagation loss of 0.62 dB/mm and a bend loss of 0.81 dB/9...

2015
Giorgio Pia Francesco Delogu

The present work focuses on the development of a theoretical model aimed at relating the mechanical properties of nanoporous metals to the bending response of thick ligaments. The model describes the structure of nanoporous metal foams in terms of an idealized regular lattice of massive cubic nodes and thick ligaments with square cross-sections. Following a general introduction to the subject, ...

Journal: :Optics express 2015
Seung-Min Lee Su-Hyun Gong Jin-Ho Kang Mohamed Ebaid Sang-Wan Ryu Yong-Hoon Cho

Laser operation of a GaN vertical cavity surface emitting laser (VCSEL) is demonstrated under optical pumping with a nanoporous distributed Bragg reflector (DBR). High reflectivity, approaching 100%, is obtained due to the high index-contrast of the nanoporous DBR. The VCSEL system exhibits low threshold power density due to the formation of high Q-factor cavity, which shows the potential of na...

2017
Bodo D Wilts Benjamin Apeleo Zubiri Michael A Klatt Benjamin Butz Michael G Fischer Stephen T Kelly Erdmann Spiecker Ullrich Steiner Gerd E Schröder-Turk

The formation of the biophotonic gyroid material in butterfly wing scales is an exceptional feat of evolutionary engineering of functional nanostructures. It is hypothesized that this nanostructure forms by chitin polymerization inside a convoluted membrane of corresponding shape in the endoplasmic reticulum. However, this dynamic formation process, including whether membrane folding and chitin...

Journal: :Physical chemistry chemical physics : PCCP 2011
Masataka Hakamada Masaki Takahashi Toshiyuki Furukawa Kazuki Tajima Kazuki Yoshimura Yasumasa Chino Mamoru Mabuchi

Desorption of thiolate self-assembled monolayers (SAMs) seriously limits the fabrication of thiol-based devices. Here we demonstrate that nanoporous Au produced by dealloying Au-Ag alloys exhibits high electrochemical stability against thiolate desorption. Nanoporous Au has many defective sites, lattice strain and residual Ag on the ligament surface. First-principles calculations indicate that ...

Journal: :journal of advanced materials and processing 0
maryam shojaie bahaabad department of chemical and materialas engineering, shahrood university of technology, shahrood, iran

in this work, sio2 –zro2 mixed oxides was prepared by the polymeric sol–gel route. the characterization of pore structure, which determines the permeation process of membrane, is of great importance. so far, most investigations have focused on such pore structure as specific surface area and pore size distribution, but the surface fractal, the important parameter reflecting the roughness of por...

Journal: :The Journal of chemical physics 2014
Chongqin Zhu Hui Li Sheng Meng

Water transport through a two-dimensional nanoporous membrane has attracted increasing attention in recent years thanks to great demands in water purification and desalination applications. However, few studies have been reported on the microscopic mechanisms of water transport through structured nanopores, especially at the atomistic scale. Here we investigate the microstructure of water flow ...

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